Defn: Same as Prothyalosoma.
PROTIST
Pro"tist, n. (Zoöl.)
Defn: One of the Protista.
PROTISTA
Pro*tis"ta, n. pl. Etym: [NL., fr. Gr. prw`tistos first.] (Zoöl.)
Defn: A provisional group in which are placed a number of low microscopic organisms of doubtful nature. Some are probably plants, others animals.
PROTISTON
Pro*tis"ton, n.; pl. Protista. Etym: [NL.] (Zoöl.)
Defn: One of the Protista.
PROTO-
Pro"to-. Etym: [Gr. prw os first, a superl. fr. Pro-.]
1. A combining form prefix signifying first, primary, primordial; as, protomartyr, the first martyr; protomorphic, primitive in form; protoplast, a primordial organism; prototype, protozoan.
2. (Chem.) (a) Denoting the first or lowest of a series, or the one having the smallest amount of the element to the name of which it is prefixed; as protoxide, protochloride, etc. (b) Sometimes used as equivalent to mono-, as indicating that the compound has but one atom of the element to the name of which it is prefixed. Also used adjectively.